This invention relates generally to a point detonating fuse for high explosive mortar ammunition, and more particularly to a fuse which upon target impact will produce a near surface burst of the mortar shell, thereby, maximizing the fragmentation dispersal and increasing the lethality of the shell.
Current mortar ammunition often is ineffective because it bursts essentially at ground level with minimum fragmentation dispersal. Intensive, costly development has been directed toward improving the effectiveness of mortar ammunition, and toward this end, expensive proximity and time controlled fuses have been proposed to produce a near surface burst at about 3 to 8 feet above the target surface.
Proximity fuses commonly employ complicated electronic sensing devices intended to sense approaching target areas. However, they are seriously affected by conditions such as climate, rain, sleet, snow, tree foilage, and vegetation. Hence, the fuses often are triggered prematurely or late, or not at all, thus rendering the mortar shells ineffective.
Time fuses require a gun crew to estimate target range and then equate it to time within a tenth of a second setting on the fuse clock controls. Many variables affect flight time of a round, such as variation in weight, propellant powder, clearances between the round and bore of the barrel, in-flight conditions such as air density, temperature, wind, etc., any of which may cause an early or late burst based solely on time.
Some years ago the German Army proposed a mortar shell known as the "Bouncing Betty" in which, upon impact, a nondelay fuse assembly was intended to ignite a powder charge to throw the shell into the air before the main charge was detonated. However, apparently because of poor design, this proposal proved unsuccessful and was abandoned.